exit(0);
}It draws a red cross on my screen and then shows the texture i loaded. My problem now is that the texture is shown without issues. But from the point i call glTexImage2D at the lines i paint arent shown anymore they just disappear! And i have no idea why. If i comment the call of glTexImage2D out of source it works the lines are drawn (the texture is missing, logicaly). Can you help me? I allready posted in many other forum but never got any proper help.

You never disable texturing, so after loading the texture, not only is your quad textured, but so are your lines. Commenting out the glTexImage2D call helps because without the call the texture isn't initialized and texturing is disabled automatically.

Add glEnable(GL_TEXTURE_2D) and glDisable(GL_TEXTURE_2D) around your quad draw code to fix the problem.